Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1
    gardensatty's Avatar
    gardensatty is offline Main Sequence
    Points: 6,345, Level: 54
    Level completed: 98%, Points required for next Level: 5
    Overall activity: 0%
    Achievements:
    365 Days+ Registered Achievement!5 Threads Achievement!50 Posts Achievement!First 1000 Experience Points750 Days+ Registered Achievement!
    Join Date
    Mar 2011
    Location
    Palm Beach, Florida
    Posts
    59
    Points
    6,345
    Level
    54
    Thanks
    186
    Thanked 7x 6 Posts

    Default Focal Reducer - 2 Questions



    Under what circumstances would you use a focal reducer (i.g. Antares f/6.3), in combination with what other accessories? I should add that this is for a f/10 scope (CGEM DX 1100 HD).
    Last edited by gardensatty; 11-21-2011 at 09:34 PM.

  2. The Following User Says Thank You to gardensatty For This Useful Post:

    Bagpiper (11-27-2011)

  3. #2
    KathyNS's Avatar
    KathyNS is offline Super Moderator
    Points: 172,794, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 36.0%
    Achievements:
    200+ Posts Achievement!Ghost Achievement! Averaging 5+ posts a day!First 1000 Experience Points400+ Posts AchievementGot three Friends
    Awards:
    Reply Award
    Join Date
    Nov 2010
    Location
    Nova Scotia
    Posts
    25,165
    Points
    172,794
    Level
    100
    Thanks
    6,659
    Thanked 14,981x 9,540 Posts
    Blog Entries
    3

    Default

    A focal reducer is a lens that reduces the effective focal length of a scope. You would use one to increase the field of view by decreasing the magnification. You would also use it to increase the amount of light available for astrophotography by reducing the focal ratio.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    DSO AP:
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    (pier);
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    .

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  4. The Following 2 Users Say Thank You to KathyNS For This Useful Post:

    gardensatty (11-21-2011),tmohr (11-21-2011)

  5. #3
    MadCrawdad's Avatar
    MadCrawdad is offline SUPER GIANT
    Points: 12,530, Level: 77
    Level completed: 38%, Points required for next Level: 220
    Overall activity: 0%
    Achievements:
    200+ Posts Achievement!First 1000 Experience Points400+ Posts Achievement365 Days+ Registered Achievement!750 Days+ Registered Achievement!
    Join Date
    Sep 2010
    Location
    Chicagoland
    Posts
    954
    Points
    12,530
    Level
    77
    Thanks
    337
    Thanked 432x 315 Posts

    Default

    I see that you have a Celestron HD model. Be aware that any old focal reducer won't work with that scope. Celestron is developing one, and another company (OPTEC) has recently come out with one, but as the optics on the HD are already corrected for coma and flatness of field, the field flattener in most FRs will push the optics past the point of correction, and then give you problems on the other side.
    Mike

    Meade 8" LX200-ACF ~
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    4SE ~ Meade 8" LX50 ~
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ST80 ~ Meade Wedge
    Meade DSI II PRO ~ Meade DSI II Color ~ Canon EOS Rebel XSi/450D

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


  6. The Following 2 Users Say Thank You to MadCrawdad For This Useful Post:

    gardensatty (11-22-2011),tmohr (11-21-2011)

  7. #4
    gardensatty's Avatar
    gardensatty is offline Main Sequence
    Points: 6,345, Level: 54
    Level completed: 98%, Points required for next Level: 5
    Overall activity: 0%
    Achievements:
    365 Days+ Registered Achievement!5 Threads Achievement!50 Posts Achievement!First 1000 Experience Points750 Days+ Registered Achievement!
    Join Date
    Mar 2011
    Location
    Palm Beach, Florida
    Posts
    59
    Points
    6,345
    Level
    54
    Thanks
    186
    Thanked 7x 6 Posts

    Default

    Ouch! Thank you. That is extremely heplful. Wish I knew that information before I acquired the FR.

  8. #5
    Bob327's Avatar
    Bob327 is offline HYPER GIANT
    Points: 41,366, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    10 Days registered200+ Posts Achievement!First 1000 Experience PointsGot three Friends365 Days+ Registered Achievement!
    Join Date
    Sep 2009
    Location
    Frederick Maryland
    Posts
    9,247
    Points
    41,366
    Level
    100
    Thanks
    19
    Thanked 4,039x 3,068 Posts

    Default

    I do use a Denkmeier Powerswitch 2 inch diagonal on my CPC1100 ..the Denk has a built in 2x Barlow and a 0.6 (not 0.63) Focal reducer...and I love the darn thing and normally view in reduced mode the majority of the time..rarely ever use the barlow however ...

    BUT as mentioned above the New Edge Scopes will NOT work with a regular Focal reducer... Celestron promised one for the HD scopes but has of yet to deliver ... Selling the Antares should not be a problem however ..you gambled and lost...been there done that quite a bit myself...

    Bob G
    CPC1100 housed in a slotted domed observatory (Exploradome) 4 and 5 inch refractors for use from the lawn, a 8" Sct (NS 8i) for star parties...
    I Hate the winter so I use heated Motorcycle clothing to stay warm while observing in winter
    Retired, also have 2 other hobbies
    1. tinker with older Corvettes (6 in garage)
    2. make a heck of a lot of sawdust in my wood shop.

  9. The Following 3 Users Say Thank You to Bob327 For This Useful Post:

    gardensatty (11-22-2011),stewarttt (11-23-2011),tmohr (11-23-2011)

  10. #6
    gardensatty's Avatar
    gardensatty is offline Main Sequence
    Points: 6,345, Level: 54
    Level completed: 98%, Points required for next Level: 5
    Overall activity: 0%
    Achievements:
    365 Days+ Registered Achievement!5 Threads Achievement!50 Posts Achievement!First 1000 Experience Points750 Days+ Registered Achievement!
    Join Date
    Mar 2011
    Location
    Palm Beach, Florida
    Posts
    59
    Points
    6,345
    Level
    54
    Thanks
    186
    Thanked 7x 6 Posts

    Default

    I called Celestron and they are not close to a focal reducer for my scope.

  11. #7
    MadCrawdad's Avatar
    MadCrawdad is offline SUPER GIANT
    Points: 12,530, Level: 77
    Level completed: 38%, Points required for next Level: 220
    Overall activity: 0%
    Achievements:
    200+ Posts Achievement!First 1000 Experience Points400+ Posts Achievement365 Days+ Registered Achievement!750 Days+ Registered Achievement!
    Join Date
    Sep 2010
    Location
    Chicagoland
    Posts
    954
    Points
    12,530
    Level
    77
    Thanks
    337
    Thanked 432x 315 Posts

    Default

    There is this one below. In addition to the telecompressor, you'd also need to buy the camera mount specific to your camera (search Lepus Camera Adapter on the OPT website). Can't say how well they work, though.

    Optec Lepus HD Telecompressor ? Celestron C11 EdgeHD Edition - OPT Telescopes
    Mike

    Meade 8" LX200-ACF ~
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    4SE ~ Meade 8" LX50 ~
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ST80 ~ Meade Wedge
    Meade DSI II PRO ~ Meade DSI II Color ~ Canon EOS Rebel XSi/450D

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


  12. The Following User Says Thank You to MadCrawdad For This Useful Post:

    gardensatty (11-23-2011)

  13. #8
    gardensatty's Avatar
    gardensatty is offline Main Sequence
    Points: 6,345, Level: 54
    Level completed: 98%, Points required for next Level: 5
    Overall activity: 0%
    Achievements:
    365 Days+ Registered Achievement!5 Threads Achievement!50 Posts Achievement!First 1000 Experience Points750 Days+ Registered Achievement!
    Join Date
    Mar 2011
    Location
    Palm Beach, Florida
    Posts
    59
    Points
    6,345
    Level
    54
    Thanks
    186
    Thanked 7x 6 Posts

    Default

    That's great Mike. I'll take a good look at it. Thanks. DW

  14. #9
    MadCrawdad's Avatar
    MadCrawdad is offline SUPER GIANT
    Points: 12,530, Level: 77
    Level completed: 38%, Points required for next Level: 220
    Overall activity: 0%
    Achievements:
    200+ Posts Achievement!First 1000 Experience Points400+ Posts Achievement365 Days+ Registered Achievement!750 Days+ Registered Achievement!
    Join Date
    Sep 2010
    Location
    Chicagoland
    Posts
    954
    Points
    12,530
    Level
    77
    Thanks
    337
    Thanked 432x 315 Posts

    Default

    Quote Originally Posted by gardensatty View Post
    That's great Mike.
    Not when you see the prices....
    Mike

    Meade 8" LX200-ACF ~
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    4SE ~ Meade 8" LX50 ~
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ST80 ~ Meade Wedge
    Meade DSI II PRO ~ Meade DSI II Color ~ Canon EOS Rebel XSi/450D

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


  15. #10
    kirstentoh's Avatar
    kirstentoh is offline White Dwarf
    Points: 558, Level: 11
    Level completed: 16%, Points required for next Level: 42
    Overall activity: 0%
    Achievements:
    365 Days+ Registered Achievement!2 Posts Achievement20 Posts Achievement!
    Join Date
    Nov 2011
    Location
    Malaysia
    Posts
    22
    Points
    558
    Level
    11
    Thanks
    5
    Thanked 1 Time in 1 Post

    Default

    If I have a f/13 scope , what does a f/6.3 focaler do to the focal length? I guess what I am trying to ask is how does one compute effective focal length after fixing in a focal reducer of a certain denomination?

 

 
Page 1 of 2 12 LastLast

Similar Threads

  1. Focal Reducer, how much is too much?
    By patm in forum CCD Imaging Forum
    Replies: 1
    Last Post: 10-02-2009, 08:07 PM
  2. Focal Reducer does what?
    By patm in forum CCD Imaging Forum
    Replies: 5
    Last Post: 09-24-2009, 10:18 PM
  3. Help! My Focal Reducer won't fit!
    By Kiwi Steve in forum Amateur Astronomy Forum
    Replies: 9
    Last Post: 03-13-2005, 08:56 PM
  4. C9.25 and focal reducer
    By misaligned astronomer in forum Amateur Astronomy Forum
    Replies: 10
    Last Post: 07-18-2004, 07:59 PM
  5. Focal Reducer
    By Ian Piper in forum UK Astronomy Forum
    Replies: 1
    Last Post: 05-23-2004, 04:34 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 01:42 AM.